Unaudited Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 25,628	$ 19,444	$ 69,098	$ 54,758
Other Comprehensive Income, Net of Tax
Unrealized (losses) gains on available-for-sale securities	(21,600)	8,733	(77,285)	31,965
Reclassification adjustment for losses included in net income	403	0	299	0
Net unrealized (losses) gains on securities	(21,197)	8,733	(76,986)	31,965
Tax effect	8,246	(3,398)	29,948	(12,435)
Net of tax amount	(12,951)	5,335	(47,038)	19,530
Unrealized (losses) gains on derivatives used for cash flow hedges	(735)	(2,507)	14,827	(8,446)
Tax effect	287	975	(5,768)	3,285
Net of tax amount	(448)	(1,532)	9,059	(5,161)
Total other comprehensive (loss) income, net of tax	(13,399)	3,803	(37,979)	14,369
Total Comprehensive Income	$ 12,229	$ 23,247	$ 31,119	$ 69,127